Cool. I'll look for them.
I've been hitting EPay and there are some good options out there it seems if you search hard enough. The hard part is making sure you don't get a FILM holder instead of a PLATE holder. It seems dicey with some of these guys. But Zeiss and others made 4x5 plate cameras and whole cameras with holders are available.
My BIG concern is a lack of standards. I have no idea what was "standard" back then. So any help would be useful.
It APPEARS that Graflex made plate holders at some point and they can be had readily. I am not worried about the PLATE size, but if the thing will fit readily on a 4x5.
Here are some description I have found. If anyone knows if these will work, let me know.
Desc: Double Graflex Plate Holder wood framed with metal slides and brass locks. Marked Folmer Graflex Corp., U.S. Pat. and 4 X 5 Graphic Film. Are ½ thick,4 ¾ wide by 6 ¾ long to the top of the handle. Holder shows some rust on the handle frame. Slides and inside are very good.Desc: Wood framed Graflex double Plate Holder very clean with aluminum pull handles. Marked 3 ¼ X 4 ¼ Gralex Film U.S. Pat. Measures ½" thick, 4 ¼ wide by 6 to top of handle.(VG)Desc: The Premo Camera" double Plate Holder, wood framed and pull handles, is ½ thick, 4 ¾ wide and 6 ½ long to top of handle. One handle was replaced with a home made hand and it works just as good as the other plus adds some corrector to it. (G)